Tuning device



A ril 20, 1926. 1,581,900

G.H.WHWTWGHAM TUNING DEVICE Filed August 28, 1924 ondary or gri Patented Apr. 20, 1.926.

UNITED STATES H I l 1,581,900 PATENT O-FFHCE.

' GEORGE E. WHITTINGHAM, OF BALTIMORE, MARYLAND, ASSIGNOR TO MONITOR CON- TBOLLER COMPANY, OF BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND.

TUNING DEVICE.

Application filed August 28,1924. Serial No. 734,670.

at Baltimore, in the State of Maryland, have invented certain new and useful Improve,

ments in Tuning Devices of which the following is a speclficatfchi.

This invention relates to tuning devices, and more particularly to an inductive coupling between the primary and secondary inductance of an apparatus for receiving radiant ener In radio receivin apparatus, it is usua ly referable to embody a seccircuit, which is inductively coupled to the primary circuit, instead of being a wing circuit directly connected thereto. One of the objects of the invention is to provide a structure of maximum efficiency for coupling the rimary and secondary circuits without direct electrical connection. A further object of the invention is to so couple the rimary and secondary circuits that the tic gr coil can be placed in maximum inductive relationship with both the primary and secondary inductances simultaneously. A further object is to provide a structure of this type in which the caplacity between the prlmary inductance an a is relatively large, and such that the primar inductance and such portion of the secon ary inductance bear the same capacitative relation to the tickler'at all'times. A still further hb'ect of the invention is to provide simple an efficient mounting means for the support on which the inductances are wound and for the tickler coil. Still further objects of the invention and features of novelty will be applarent from the following description w en taken in conjunction with the accompanying drawings, in which:

.Fig. 1 is a pers device embodying t e invention as it appears when mounted upon a panel, the panel and operating knob being shown as broken away to more clearly disclose the structure;

- Fig. 2 is a fragmentary view inelevation of the form and windings shown in Fig.1; Fig. 3 is a view in side elevation, artly in section of the structure shown in shown in Fig. 1; and,

Fig. 5 is a detail of the supporting bracket shown in Figs. 1 and 3. f As shown in the drawings, the primary rtion of the secondary inductance.

live view of a tuning ig. 1" Fig. 41s a plan view of the tickler coil and secondary inductances are wound upon a cylindrical tube or form 11, upon which binding posts 12, 13, 14, and 15 may beconveniently mounted, the primary circuit extending between binding posts 12 and 13, and the secondary between binding posts 14 and 15. The secondary circuit is divided into threev ortions, the end portions comprising win ings 16 and 17, preferably equal in number, and the central portion comprising windings 18 which are formed into a twisted pair with the windings 19 of the pri-'. mary inductance. Thus, the primary inductance as well as that portion of the secondary inductance with which it is most closely coupled, comprises a helix wound upon a cylinder and any portion of the primary winding may be considered as exactly superposed upon the corresponding portion of the secondary winding.

The tickler coil 20- may take any suitable and convenient form, such .as that shown in Figs. 1 and 4, in which a'plurality of turns are laterally spaced to form a helix and are spaced radially, by a zig-zag turn from the next row of helical turns. It will be understood that a duo lateral, or other similar coil of low distributed capacity, maybe used.

The tube or form 11 is adapted to be support-ed from a anel by means of a bracket 21, formed ass own in Fig. 5'. This brack- 'et may be stamped from sheet metal and bent to the form shown, having a fiat top 24 which may be curved to fit the tube 11. and which may be secured thereto by-rivets 25, or any other suitable. means. 'A tubular bolt 26 is adaptedto pass through the anel 27 and make threaded engagement wit the flat portion of the support 21. As shown in Fig. 3, the inner end of the bolt 26 is split at 28 and the parts'bent together to. frictionally engage a shaft 29 which extends through the tubular boltand is adapted; to, be moved by a-knob 30, of any desired construction. Y p .1 The tickler coil is provided with a round support memberzfl, having a hole 32 therein to frictionally receive the shaft 29. The support member 31' may be conveniently made of wood and the. coil is'preferably se-- cured on the ends thereof by some suitable adhesive, while the opening 32is held prop- HEBSU D an angle of coil which, in the construction shown, is at It will be understood that f the ends 33 and 34 of the coil may be carried to suitable bindingposts on the. form.

' the form 11 and passing the en s of the primary windin down through the form or tube 11, and hence to the binding posts 12 and 13. The end portions of the secondary winding may then .be wound on to the form 11 in opposite directions and passed through to contact with the binding posts 14 and 15.

It will be noted. that the support for the inductance is simple and entails making only one hole to permit its support from a panel. The grip of the split ends of the bolt 26 upon the shaft 29 is sufficient to hold the tubular coil in position at all times and the tickler coil may be readily-changed or mounted bymerely twisting the shaft 29 through the bolt 26 and the coil support 31.

The tickler coil may be readily adjusted so that its central plane will coincide with the central planes of the primary and secondary inductances and the device as a whole may be readily assembled or dismounted.

It will also be noted that the primer windings and those windings of the secon ary which are twisted with the primary bear the same equal capacitative relation to the tickler windings, neither the primary nor the secondary windings bei interposed between the other and the tick er except where they cross.

I It will be understood that many changes may be made in the design and construction of the 'parts without departing from the spirit of the invention, which is defined in the following claims.

What I claim is:

1. A "transformer comprising a twisted pair of conductors, one conductor of said pair being continued beyond its wisted portion and formed into successive turns adapted to increase the inductance of its twisted portion. p

2. A transformer comprising primary and secondary windin s, one of said windings and a ortion of t e other of said windings being in the form of a twisted pair and formed into a closed coil to increase their inductance.

3. A transformer comprising a conductor .which their central planes and axes coincide.

wound in successive turns about an axis and B a second conductor having a central portion twisted upon said first named conductor as it extends about said axis, and end portions formed in successive turns in inductive relationship to said central portion.

' 4. A transformer comprising primary and secondary conductors having portions thereof formed in a twisted pair and a third conduc tor havin its axis and central lane coincident Wit 1 the axis and central p ane of said twisted pair portions.

5. A tuning device, comprising an inductance formed by a conductor wound in successive turns about an axis, a second inductance formed by a conductor having a portiontwisted about said first conductor as it extends about said axis, and a third inductance, said primary and third inductances being relatively adjustable to a position in 8O 6. A tuning. device, comprising primary and. secondary windings, portions of said windings being twisted about each other to form a twisted pair and formed into aplosed coil, and a third winding adjustable relative to said primary and secondary windings andhaving equal capacitative' relation to the twisted portions of said primary and secondary windings.

. A tuning device, comprising primary and secondary windings having portions thereof closely associated with each other to form a substantial capacitative coupling between them, and a third winding, said primary and secondary windings as a unit and said third winding being relatively adjustabio, and the closely associated portions of said primary and secondar 1 windings having egual capacitative relation to said third winding.

8. A tuning device comprising a primary inductance having a plurality of successive turns, a secondary inductance having a numher of turns thereof closely associated with the turns ofthe-primary inductance to form a substantial capacitative coupling therewith, and a third inductance, said primary and secondary inductances asa unit and said third inductance being relativel adjustable, the turns of said primary in uctance and those turns of the secondary inductance closely associated therewith being so arranged as to'have identical capacitative relation to said third inductance.

In testimony whereof I hereunto afiix my signature. i

GEORGE H.- WHITTlNGHAM- 

